i’m wondering if anyone out there has experience with using concrete to build a cantilevered deck. i’d like to build decks on three sides of a home that will be situated on a ridgetop. it’d be great to extend the decks out ten feet from the foundation walls. i’m pretty sure this is doable, i suppose it requires a lot of steel and a relatively thick slab of concrete to be able to support it’s own weight way out there. there won’t be anything other than a stucco wall at railing height around the perimeter and stone floor covering, so it’s mostly supporting itself. well, then you’d want to be able to load it up with people at some point. i’m not sure how much it matters in the case of concrete but i’ve got plenty of “inboard” slab, more than twice the overhang. i’m familiar with the concept of post tensioning but have never been involved with that sort of thing. is it necessary? and has anyone here dealt with a similar situation? thanks in advance.
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It sounds quite doable. I am always surprised by how thin the cantilevered decks in hi-rises are. I remember drawing the 8" slab continuing out to form a 6'-0" deck on a building, and having to revise it when the structural drawings came back and it was 6" at the exterior wall, and only 4" at the railing. Packed full of steel, but none of it post-tensioned.
Its all in the steel work, the shape, and the mix. You will have to get it engineered for sure. 10' is a lot of weight out there.
i ran it by my structural engineer over the phone and he seems to think it can be done. i'm very curious about this.
Certainly no more complicated than Falling Water and similar structures. I don't know that the concrete would even have to be that thick, if one wants to put a lot of effort into detailed engineering and high-tech concrete. Post-tensioned concrete might be the ideal choice.
With cantilevered structures, though, one thing to consider is how much counter-balancing weight is needed. Best if that can be designed in -- making use of structure you'll be building anyway, vs just pouring more concrete for dead weight.
yeah, it's pretty amazing how they hung those things out there at falling water. i read about the fix they used because they were drooping quite a bit. the whole retrofit was featured in some magazine a while back. i wonder if it was fhb, heh, heh? anyway, that's partially the inspiration for what i'm going to attempt. this ought to be entertaining.
Yeah, Wright liked to push the envelope, and had a certain degree of distain for regular engineers and regular "engineering margins", so some of his designs did not hold up remarkably well over decades. But none have collapsed either, that I know of.(Aha!! A "margin of engineers"!)
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
But why would you place a stucco wall at railing height? Why not a simple round railing with glass below or at least something you can look through.
Heck, make the whole deck out of glass!
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck
have you seen the circular glass staircase/elevator at the apple store on 5th avenue in nyc? it's one of the most amazing structures i've ever come across! i want to use stucco for privacy though, similar to what falling water looks like.
No, I don't hit 5th Ave that often.
People never lie so much as before an election, during a war, or after a hunt. --Otto von Bismarck